Complex forming polymers from dimethyl dipyridyl compounds

ABSTRACT

COMPLEX FORMING POLYMERS, HAVING REPEAT UNITS   (PYRID-2-YL-L-)PYRIDINE   JOINED TO EACH OTHER BY POLYVALENT LINKING GROUPS, WHERE L IS A DIRECT BOND OR AN O, S, CO, CHR1 OR NR1 LINK (R1 BEING HYDROGEN OR ALKYL) AND THE PYRIDYL RINGS MAY BE SUBSTITUTED BY ALKYL OR LINKED TO EACH OTHER AT POSITIONS ORTHO TO THE L LINK BY A -CR1=CR1 GROUP, ARE USEFUL FOR COMPLEXING NON-ALKALINE METAL ATOMS. THEY WILL FORM COMPLEXES IN AN ACIDIC MEDIUM AND WHEN THE METAL IS ITSELF ALREADY PART OF A COMPLEX ION. THE COMPLEXED POLYMERS ARE USEFUL AS CATALYSTS AND, AS ARE THE COMPLEX FORMING POLYMERS, AS VARNISHES FOR COATING METAL. THE POLYMERS ARE PREPARED BY A VARIETY OF VINYL-TYPE POLYMERIZATIONS AND POLYCONDENSATIONS. PARTICULARLY USEFUL INTERMEDIATES   2-(4-(OCH-AR-CH=CH-)PYRID-2-YL),4-(OCH-AR-CH=CH-)PYRIDINE   WHERE AR IS ARYL ARE PREPARED FROM THE ARYL DIALDEHYDE AND 4,4&#39;&#39;-DIMETHYL-2,2&#39;&#39;-DIPYRIDYL.

US. Cl. 260--2. R 3 Claims ABSTRACT OF THE DISCLOSURE Complex formingpolymers, having repeat units joined to each other by polyvalent linkinggroups, where L is a direct bond or an O, S, C0, CHR, or NR link (Rbeing hydrogen or alkyl) and the pyridyl rings may be substituted byalkyl or linked to each other at positions ortho to the L link by a -CR=CR group, are useful for complexing non-alkaline metal atoms. They willform complexes in an acidic medium and when the metal is itself alreadypart of a complex ion. The complexed polymers are useful as catalystsand, as are the complex forming polymers, as varnishes for coatingmetal. The polymers are prepared by a variety of vinyl-typepolymerizations and polycondensations. Particularly useful intermediateswhere Ar is aryl are prepared from the aryl dialdehyde and4,4'-dimethyl-2,2'-dipyridyl.

This is a division of application Ser. No. 59,024, filed July 28, 1970,now abandoned.

The present invention relates "to new complex forming' polymers, toprocesses for their preparation, to various applications of thesepolymers and to certain monomers useful in the preparation of thepolymers.

Various types of complex-forming polymers are known. Their principalvalue resides in their ability to complex certain metal ions.

The complex-forming polymers according to the present invention aremacromolecular compounds containing repeat units of formula:

the said units of Formula I being joined together by one or morepolyvalent radicals R.

United States Patent ice is purely formal in character and that, inreality, the elec' trons are delocalized in accordance with theclassical state of aromatic nuclear systems.

The polyvalent radical R, which is a linking agent may representradicals R or R as set out below.

R represents an organic or inorganic divalent radical which can, forexample, consist of a radical or a succession of several radicals R Rand Y, as follows:

R represents a saturated or unsaturated, linear or branched alkyleneradical which may optionally carry hydroxyl or 0x0 substituents and mayoptionally carry alkano or alkeno bridges, with the total number ofcarbon atoms of the radical R being preferably less than 12. Rrepresents an arylene radical such as phenylene, or a divalentheterocyclic radical, and

Y represents an radical, R being a lower alkyl radical or an arylradical such as phenyl.

R represents a polyvalent macromolecular radical, for example, offormula:

CD... \M. in which K represents a trivalent organic radical, Qrepresents a tetravalent organic radical, m represents a positiveinteger, and K, Q and m are such that {-KH} and 401m represent polymerssuch as polyolefines, polyethers, polyamides, polyesters, polyimides,polyurethanes,

vinyl polymers or acrylic polymers.

The complex-forming polymers derived from linking agents of type R arecalled complex-forming polymers of type P and the derivatives of linkingagents of type R are called complex-forming polymers of type P Thecomplex-forming polymers of type P consist of an alternation of units ofFormula I and linking agents R The complex-forming polymers of type Pconsist of a macromolecular chain on which the units of Formula I tormside branches and can optionally simultaneously be linked to othermacromolecular chains. In this specification, the term lower alkyl groupmeans one having up to 6 carbon atoms.

Various processes for the preparation of complex-forming polymersaccoding to the invention can be used.

According to a first group of methods of preparation, polymerization iscarried out employing at least one dinitrogenous monomer having at leastone suitable reactive group (by a dinitrogenous monomer we mean amonomer of which all or at least part of the structural skeleton isidentical to the skeleton of the compound of formula:

in which a, a and a' have the name meanings respectively as a, a and ain Formula 1, above except they do not represent a valency bond).

This polymerization can be a so-called vinyl polymerization or apolycondensation.

If a vinyl polymerization is carried out, the dinitrogenous monomer maybe derived from the compound of Formula H and have one or moreolefinically unsaturated substituents, such as substituents of formulae:

in which S S S and S which may 'be identical or different, eachrepresent hydrogen or a lower alkyl group.

If a polycondensation is carried out, the dinitrogenous monomer employedmay be derived from the compound of Formula II and have one or moresubstituents which can participate in polycondensation reactions.

For the purpose of preparing complex-forming polymers of type P themonomers preferably are of formula:

N N c e f1 Ill a: It (III) in which f and f which may be identical ordifierent,

each represent reactive groups of formula -RZ, wherein R' represents avalency bond or a radical or a succession of radicals such as R R and Y,of which the two free 'valencies are carried by carbon atoms, and Zrepresents a group such as formyl, amino, hydroxyl, hydroxycarbonyl,chlorocarbonyl, or isocyanato and can also represent hydrogen in thecase where R represents a methylene radical.

The dialdehyde monomers of Formula III, in which f and f have theformula -R'CHO, can be polycondensed with ketones or amines.

Their polycondensation with ketones can, for example, be carried out inaccordance with the techniques described in Belgian Pat. No. 714,325. Ifthe ketone has the formula:

by by in which the suffix hy placed under a double bond indicates thatthe latter can optionally be in the hydrated form (-CHO'H CH Thepolycondensation of a dialdehyde monomer of Formula III in which f and fhave the formula with a diamine can be effected in accordance with thevarious techniques described by G. F. dAlelio et al. (I. Macromol. Sc.,A (2), 237333 (1968)). If the diamine employed has the formula NH -R NHin which R is a radical or a succession of radicals such as R R and Y,of which the two free valencies are carried by carbon atoms, thecomplex-forming polymer so obtained comprises repeat units of formula:

in which R represents a tetravalent organic radical containing at leasttwo carbon atoms, the polymer thus obtained comprises repeat units offormula:

If a diamine monomer of Formula III in which f and f represent -R'-NHradicals is polycondensed with a diisocyanate of formula OCNR -NCO inwhich R has the meanings given for R a polymer with urea units isobtained having repeat units of formula:

-L a1 (12 NHOONH-R9NHCONH- Dimethylated monomers of formula:

can give rise to polycondensates in various ways.

Under the dehydrogenating action of sulphur, they can give rise tocomplex-forming polymers having repeat units of formula:

N N -L- This polycondensation can be carried out in accordance with atechnique similar to that known for the picolines the dimethylatedmonomers of Formula IV can give rise to complex-forming polymerscomprising repeat units of formula:

This latter polycondensation can he carried out by simple heating of themixture of the reagents, preferably in the presence of a dehydratingagent and at a temperature above 100 C.

The dimethylated monomers of Formula IV can furthermore be polycondensedwith dihalogenated derivatives of formula X-R'r-X wherein X represents ahalogen atom and R represents a divalent radical as defined above. Theresulting complex-forming polymers have repeat units of formula:

(l2 CHg-R This polycondensation can be achieved in accordance with atechnique similar to that known for the picolines (R. Wegler et al.,Ben, 83, 610 (1950)).

Dihydroxy monomers of Formula III in which f and f represent -R'-OHradicals can give rise to complexforming polymers by reaction withdiacids, dianhydrides or dichlorides of acids (to give polyesters) ordiisocyanates (to give polyurethanes).

Dicarboxylic monomers of Formula III in which and f represent -R'COOHradicals can give rise to complex-forming polymers by reaction withdiols (to give polyesters) or diamines (to give polyamides).

Isocyanato monomers of Formula III, in which f and f represent R--NCOradicals can give rise to complex-forming polymers by reaction withdiols (to give polyurethanes) or diamines (to give polyureas).

According to a further method of preparing the complex-forming polymersaccording to the invention, a dinitrogenous monomer is attached to aprevious y produced polymer. It is, for example, possible to react apolymer of formula with a dinitrogenous monomer derived from thecompound of Formula II and having at least one substituent f' theradicals f and f being capable of reacting together in a condensationreaction.

This method of preparation gives rise to complex-forming polymers of thetype P defined above.

Examples of radicals f and f include radicals having carboxyl/hydroxyl,chlorocarbonyl/hydroxyl and anhydride/hydroxyl groups, which give riseto polyesters, carboxyl/amino and chlorocarbonyl/amino which give riseto polyamides, hydroxyl/isocyanate which gives rise to polyurethanes,and hydroxyl/aldehyde which gives rise to polyacetals.

In particular, a complex-forming polymer of type P can be prepared byreacting a polymer with hydroxyl groups, such as a homopolymer orcopolymer of vinyl alcohol, in the presence of an acid, with adinitrogenous monomer having at least one aldehyde group, such as acompound of formula:

This acetalization can optionally be carried out in the presence ofother aldehydes, such as formaldehyde, or their precursors, such astrioxymethylene.

The complex-forming polymers according to the invention can, dependingon their nature and their method of preparation, be obtained in the:solid state or in solution or in suspension; they are preferably storedin the moist state, in solution or in suspension.

From amongst the numerous polymer types described above, the preferredpolymers according to the invention are:

-(1) Polymers having repeat units:

wherein R represents a divalent radical:

( s Re -R'-oH=b-c 0-b=oHR'- in which R and R represent hydrogen or analkyl radical with 1 to 4 carbon atoms or together form an alkyleneradical having 2 or 3 carbon atoms, and R represents the -CH=OH-Arradical, Ar being the m-phenylene, or p-diphenylene group, and byindicates that the double bond may optionally be hydrated, or

CH CH (c) oH=)..-

in which n has a value of 1 to 10, or

( o o o oH2)3- otm3 or N\ N- o o o 0 (2) Polymers having repeat unitslinked to one another by macromolecular radicals R having a repeat unitwherein Ar and by have the significance given above.

The preferred processes for preparation of the polymers are thosedescribed above in which the reagents are chosen to give the preferredproducts indicated above.

The present invention also relates to the application of thecomplex-forming polymers described above to the preparation of additioncompounds, especially salts of complex-forming polymers, and ofcomplexed polymers.

The salts of complex-forming polymers are obtained by linking acids notcontaining a metal atom to the units of Formula I of the complex-formingpolymers. More precisely, these salts may be prepared by reaction of theacid with the complex-forming polymer. This reaction can be carried outeither by immersing the solid complexforming polymer in a solution ofthe acid or by mixing a solution of the acid and a solution of acomplex-forming polymer.

The complexed polymers are macromolecular com pounds containing repeatunits of formula:

linked to one another by one or more linking agents R, the meanings ofR, a, a a and L being the same as those given above, and G being anon-alkaline metal atom or an ionic compound, such as salts or acidscontaining at least one non-alkaline metal atom.

The coordination bonds indicated in Formula V join the nitrogen atoms tothe metal atom contained in G. If G represents a salt, the non-alkalinemetal atom can be contained either in the anion or in the cation.

If G represents an ionic compound, the metal atom which is directlylinked to the nitrogen atoms by coordination bonds can optionally andadditionally comprise other coordination, covalent or electrovalentbonds which link it to other ions, atoms or molecules.

Examples of salts G which can be used include ordinary metal salts suchas the halides, nitrates, sulphates, phosphates, formates, acetates,propionates and stearates; salts which contain a complex cation such asthe oxo-cations derived from titanium, vanadium, zirconium andmolybdenum, hafnium, niobium, tungsten and uranium; salts containing acomplex anion such as PdCl and, more generally, anionic metal complexesof the halides, cyanides, thiocyanate, thiosulphate and orthophosphateanions.

Examples of acids containing at least one non-alkaline metal atom,include H PtCl and H PdCl and, more, generally, the acids correspondingto the previously quoted salts containing a complex anion.

The complexed polymers described above can additionally, or optionallycomprise repeat units of Formula I which have been salified by an acidwhich does not contain a metal atom, and can hence partly constitutesalts of complex-forming polymers.

Complexed polymers comprising repeat units of Formula V, in which Grepresents an ionic metal compound, can be prepared by bringing togethera solution of an ionic compound with the complex-forming polymer or oneof its salts, in the solid state or in solution.

If a complexed polymer derived from an ionic compound is preparedstarting from a solid complex-forming polymer, various techniques can beemployed such as:

(a) The complex-forming polymer, reduced to a fragmented form, such as apowder or granules, is stirred in an aqueous solution containing anionic compound, and the solid material, which is the desired complexedpolymer is then isolated.

(b) A solution of an ionic compound is brought into contact with thesolid complex-forming polymer in accordance with conventionalliquid-solid chromatography techniques.

If a complexed polymer derived from an ionic compound is preparedstarting with a solution of a complexforming polymer, it is advantageousto bring this solution together with a solution of the ionic compound.Depending on the nature of the solvents employed, of the complex-formingpolymer and of the metal ion, the complexed polymer obtained can eitherremain in solution or precipitate. Depending on the particular case, thecomplexed polymer is isolated either by filtration or by distillation ofthe solvents and removal of the non-complexed ions by Washing, or byprecipitation With a non-solvent followed by a filtration.

The preparation of complexed polymers comprising repeat units of FormulaV in which G represents a metal atom, is usually eifected by reductionof the metal atoms of a complexed polymer comprising repeat units offormula a a N N a --L a l 7 a a1 a; a

in which G represents an ionic compound derived from the metal G. Thisreduction is usually effected with hydrogen, at a temperature between 0C. and the decomposition temperature of the complex-forming polymer.

The complex-forming polymers according to the invention are particularlyvaluable in numerous industrial applications, firstly because of theirability to complex metal ions excluding alkaline ions, and of doing soeven in an acid medium, secondly, because the complex formation takesplace Without ion exchange, and finally, because of their ability tocomplex anions which are them selves complex.

Typical industrial applications include:

(a) The extraction of precious metals, of rare earths and of radioactiveelements such as uranium from their minerals,

(b) The separation of radioactive cesium from other metals,

(c) The separation of various non-alkaline metals from one another; thecomplex-forming polymers according to the invention complex certainmetals more strongly than others,

(d) The recovery of chromium salts from tannery waste liquors,

(e) The demineralization of organic solvents without introducing foreignions, for the purpose of preparing dielectric liquids, and

(f) The purification of industrial eifiuents.

( bis) It is known that the activity of bacteria used to destroy organicwaste material in industrial eflluents can be inhibited by certain metalions such as the cupric ion. The presence of frequently large amounts ofalkaline ions in these eflluents prevents the use of ion exchange resinsof the conventional type for the removal of these undesired ions. Thecomplex-forming polymers according to the invention on the other handcan advantageously be used to remove the undesired ions in thesecircumstances.

After extraction of the metal ions from the medium in question, theresulting complexed polymers can be reconverted into complex-formingpolymers, for example by elution. The eluant may be a strong acid or acomplex-forming agent such as ethylene diamine orethylenediaminotetraacetic acid.

The complexed polymers comprising repeat units of Formula V, in which Grepresents a metal atom, can be used as catalysts, especially inhydrogenation, dehydrogenation and isomerization reactions.

The complexed and complex-forming polymers according to the inventioncan also be used as varnishes for coating metals.

The present invention also provides dialdehydes of Formula III in whichal and a are hydrogen atoms and f and 7; represent R'CHO groups.

More particularly, these dialdehydes have the formula:

in which Ar represents a divalent radical comprising at least onearomatic nucleus, preferably the m-phenylene or pphenylene radical, or aradical of general formula:

OHO

CHO

wherein Ar has the previously indicated significance. The molar ratio ofdialdehyde to dimethyldipyridyl is usually between 1:1 and :1 and theymay be heated to a temperature generally above 100 C., preferably above130 C., but below the degradation temperature of the reagents and of thereaction product. Generally, the reaction temerature does not exceed 200C.

To obtain optimum yields, it is advantageous to incorporate adehydrating agent which is inert towards the reagents into the reactionmedium. To avoid local overheating of the reaction medium, it isadvantageous to carry out the process in amedium which is a solvent forthe reagents. These two procedures can be combined by incorporating intothe reaction medium a fatty acid anhydride derived from an acidpreferably possessing less than 12 carbon atoms. Acetic anhydride is onesuch anhydride which is readily available in industry.

After reaction, the dialdehyde of Formula VI can be isolated by variousmethods, especially by selectively dissolving the unreacted products,for example by means of volatile solvents such as alcohols, followed byfiltration. The dialdehyde obtained can be recrystallized using polarsolvents such as dimethylformamide or N-methylpyrro lidone-Z.

The dialdehydes according to the invention can be used as reagents inmineral analysis.

The following examples are given to illustrate the invention.

EXAMPLE 1 A complex-forming polymer of the aldehyde/ketone type isprepared:

(A) In a first stage, 4,4'-bis(p-formylstyryl)-2,2'-dipyridyl isprepared by condensation of 4,4-dirnethyl-2,2- dipyridyl andterephthaldehyde.

55 g. of 4,4-dimethyl-2,2-dipyridyl, 121 g. of ten.- phthaldehyde and180 g. of acetic anhydride are introduced into a 500 cm. fiask fittedwith a reflux condenser. The mixture is heated under reflux for 12 hoursand filtered hot; the precipitate is washed with 600 cm. of boilingacetic anhydride and then with 500 cm. of boiling pyridine and is driedat 50 C. under 200' mm. of mercury pressure for 12 hours. The resultingsolid weighs g. It is dissolved hot in 500 0111. of N-methylpyrrolidone(NMP), the solution is cooled and the product is filtered off, washedwith cm. of NMP and dried under 200 mm. of mercury pressure at 50 C. for12 hours.

79 g. of 4, 4'-bis(p-formylstyryl)-2,2'-dipyridyl of for mula:

ono--on=pn on=on-ono are obtained.

(B) In a second stage, this dipyridyl derivative is polycondensed withcyclohexanone.

14.0 g. of 4,4'-bis(p-forrnylstyryl)-2,2'-dipyridyl and 900 cm. ofdimethylformamide (DMF) are introduced into a one liter Erlenmeyerflask. The dialdehyde is dissolved by boiling the mixture. Thereafter,boiling is continued and 3.68 g. of cyclohexanone are first added,followed by 200 cm. of sodium hydroxide solution (2.5 N) added dropwiseover the course of 1 hour. The mixture is filtered hot. The precipitateis washed with 2 liters of water and dried at 50 C. under 200 mm. ofmercury pressure for 12 hours.

12.6 g. of a yellow-brown powder which is insoluble indimethylformamicle, dimethylsulphoxide and acids and which comprisesrepeat units of formula:

hy y

N \N I in which the suffix hy has the same significance as givenpreviously, are obtained.

(C) 0.1 g. of the complex-forming polymer prepared as described inparagraph (B) is stirred, at about 20 C., with 50 cm. of water in which5 micromols of cupric sulphate and 3.125 millimols of sodium sulphatehave been dissolved. After 12 hours stirring, 1.5 micromols of cupricsalt and the amount of sodium salt. initially employed remain insolution.

(D) 0.25 g. of the complex-forming polymer prepared as described inparagraph (B) is stirred, at about 20 C., with 50 cm. of water in which1 millimol of uranyl acetate has been dissolved. After 12 hoursstirring, 0.046 millimol of uranyl salt remains in solution.

(E) 0.25 g. of the complex-forming polymer prepared as described inparagraph (B) is stirred, at about 20 C., with 50 cm. of water in which1 millimol of cupric chloride has been dissolved.

After 12 hours stirring, 0.195 millimol of cupric salt remains insolution.

1 1 (F) The procedure described in paragraph (D) is repeated, replacingthe uranyl acetate by cupric acetate and the water by ethyl alcohol.

After 12 hours stirring, 0.056 millimol of cupric salt remains insolution.

EXAMPLE 2 A complex-forming polymer is prepared by polycondensation ofthe aldehyde/ketone type.

1.5 l. of dimethylformamide and 15 g. of4,4'-bis(pformylstyryl)-2,2'-dipyridyl are introduced into a 2 literflask and the mixture boiled so that the dialdehyde dissolves. Thesolution is cooled ot 55 C. and 2.32 g. of acetone and 15 cm. of a 40%by Weight aqueous solution of tetrabutyl ammonium hydroxide added. A newsolution, which in the present example and in the following example isdescribed as a collodion, is obtained. This collodion is concentrated toa volume of 200 cm. by distillation under 20 mm. of mercury pressure andis then poured into one liter of ethyl ether. The resulting precipitateis filtered off, washed with one liter of water and dried at 50 C. under200 mm. of mercury pressure for 12 hours.

14.5 g. of a polycondensate comprising repeat units:

-GH=CHCH= H C =CH- OH=GHCO are obtained.

EXAMPLE 3 Various derivatives of the complex-forming polymer prepared inExample 2 are prepared.

(A) 50 cm. of the collodion mentioned in Example 2, and 100 cm. of a M/1000 solution of cupric nitrate in dimethylformamide, both previouslyheated to 50 C. are mixed together. An immediate precipitate ofcomplexed polymer, having repeat units of formula:

A complex-forming polymer is prepared by polycondensation of adiisocyanate and a diamine.

25 cm. of freshly distilled dimethylformamide (DMF) and 4.64 g. of4,4'-diamino-2,2-dipyridyl are introduced into a 250 em. flask equippedwith a stirrer, a dropping funnel and a thermometer. 25 cm. of DMF inwhich 6.25 g. of 4,4'-diisocyanatodiphenylmethane have previously beendissolved are then run into the flask over the course of 2 minutes.After 30 minutes, the reaction mixture is poured into 800 0111. ofwater. The mixture is filtered, the precipitate is Washed with 1000 cm.of N/ 10 sulphuric acid and then with 200 cm. of water, and dried at 50C. under 200 mm. of mercury pressure. 11.2 g. of a polycondensatecomprising repeat units of formula:

are obtained.

EXAMPLE 5 400 cm. of dimethylformamide and 4.1-6 g. of 4,4'-bis-(p-formylstyryl)-2,2-dipyridyl are introduced into a one litreErlenmeyer flask, the mixture boiled to dissolve the dialdehyde andallowed to cool to 60 C. 1.08 g. of cyclohexanone and 10 g. of a 40% byWeight aqueous solution of tetrabutylammonium hydroxide are then added.This solution, which has a blood-red color, is called solution A.

A solution B is prepared by dissolving 4.76 g. of cobalt (II) chloridehexahyldrate in 200 cm. of dimethylformamide at 60 C.

The two solutions A and B are heated to 60 C. and B is then poured intoA. The mixture is cooled and filtered. The precipitate is washed withwater and dried in vacuo (200 mm. of mercury pressure) and at ambienttemperature in a desiccator containing phosphorus pentoxide, 7.6 g. of acomplex-forming polymer comprising repeat units of formula:

are obtained.

EXAMPLE 6 A complex-forming polymer is prepared by polycondensation of adianhydride and a diamine.

6.2 g. of 4,4'-diamino-2,2-dipyridyl, 7.28 g. of pyromellitic anhydrideand cm. of diamethylacetamide are introduced into a 250 cm. flaskequipped with a stirrer, a thermometer and a reflux condenser separatedfrom the ambient atmosphere by means of a tube packed with phosphoruspentoxide.

The mixture is heated to 70 C. and 10.2 g. of acetic anhydride and 0.79g. of pyridine are added. The temperature is maintained for 30 minutesand the reaction mixture is poured into 2 litres of water. Theprecipitate is filtered, washed with 2 litres of water and then driedfor 12 hours at 50 C. under 200 mm. of mercury pressure.

13.25 g. of a complex-forming polymer containing repeat units offormula:

are obtained.

13 EXAMPLE 7 300 cmfi of freshly distilled pyridine, 18.4 g. of 4,4dimethyl-2,2'-dipyridyl and 12 g. of sodamide are introduced into a 500cm. flask equipped with a stirrer, a dropping funnel and a refluxcondenser.

The mixture is stirred for 4 hours at ambient temperature and 23 g. of1,5-dibromopentane are then added dropwise. The mixture is heated underreflux for 12 hours and filtered and the product is then successivelywashed with 1000 cm. of water, 500 cmS of ethyl alcohol, 250 cm. of Nhydrochloric acid and 250 cm. of water and finally dried at 50 C. under200 mm. of mercury pressure for 12 hours.

13.5 g. of a complex-forming polymer having repeat units of formula:

(8 do GET-(CH2) s are obtained.

EXAMPLE 8 Three solutions A, B and C as defined below are mixed in a 500cm. Erlenmeyer flask:

Solution A is 0.4 g. of 4,4'-bis(p-formylstyryl)-2,2'- dipyridyldissolved in 40 cm. of dimethylsulphoxide (DMSO). Solution B is 2 g. ofpolyvinyl alcohol (saponification number: 100) dissolved in 40 cm. ofDMSO. Solution C is 2.5 N aqueous hydrochloric acid.

A fourth solution containing 16 g. of trioxymethylene dissolved in 120cm. of DMSO is thereafter added to the mixture of solutions A, B and C.

The resulting mixture is cast onto a glass plate 12 cm. x 25 cm. andkept for 48 hours at 55 C. under'au ab solute pressure of 200 mm. ofmercury. A film of complex-forming polymer consisting of polyvinylalcohol acetalised and crosslinked by bis(p-formylstyry1)-dipyridyl andby formaldehyde is obtained; this complex-forming polymer has the unitslinked to one another by macromolecular radicals having repeat unitsWhen immersed in an aqueous solution of cupric sulphate, this filmbecomes green. This color disappears on washing with ethylene diamine.

EXAMPLE 9 13 g. of p-divinylbenzene, 18.4 g. of 4,4-dirnethyl-2,2'-dipyridyl and 140 cm. of pyridine are introduced into a 500 cm. flaskequipped with a stirrer and a reflux condenser. The mixture is heated to118 C. 46 mg. of sodium are added and heating is continued for a further15 hours. The mixture is cooled and evaporated at 40 C. under 200 mm. ofmercury pressure. The residue is extracted in a Kumagawa extractor with400 cm. of ethanol for 14 10 hours. The solid which remains is dried at50 C. under 200 mm. of mercury pressure. 8 g. of a complexformingpolymer having repeat units of formula:

5 1 C H2 2)s r- 2- are obtained.

The complex-forming polymer also contains crosslinkings between chains,due to the divinylbenzene.

EXAMPLE 1 0 (A) A complex-forming polymer is prepared bypolycondensation of the aldehyde/ketone type.

1.7 l. of dimethylformamide (DMF) and 41.6 g. of4,4-bis(p-formylstyryl)-2,2-dipyridyl are introduced into a 5 litreflask equipped with a reflux condenser and a dropping funnel. Themixture is boiled to allow the dialdehyde to dissolve, and, whilst beingkept at the boil, 6.4 g. of acetone dissolved in 50 cm. of DMF followedby cm. of aqueous 2.5 N sodium hydroxide solution, added dropwise in 1hour 30 minutes are added successively. The mixture is cooled to 50 C.and 2 litres of water at ambient temperature are added whilst stirring.The whole mixture is filtered and the precipitate is washed with 6litres of water and stored moist. The complexforrning polymer obtainedhas repeat units of the same formula as that of Example 2.

Various complex-forming experiments are carried out with thiscomplex-forming polymer in suspension as follows:

(B) A complexed polymer containing palladium of degree of oxidation+II(Pd II) is prepared.

10.36 g. of the complex-forming polymer are stirred, at about 20 C.,with 500 cm. of water in which 18 millimols of hydrochloric acid and anamount of Pd -II chloride corresponding to 6500 microgram atoms ofpalladium have been dissolved. After 12 hours stirring, 50 microgramatoms of palladium remain in solution.

The complexed polymer containing Pd II is filtered 01f.

(C) A complexed polymer containing palladium of degree of oxidation zerois prepared.

0.085 g. of the polymer prepared as described inparagraph (B) are mixedwith 0.915 g. of glass beads; the mixture is introduced into a 2 cm.reactor at 350 C.; a stream of nitrogen of 0.5 1./hour is passed throughthis reactor for 15 minutes followed by a stream of hydrogen of the sameflow rate for the same time, followed again by a stream of nitrogen for15 minutes. A polymer containing palladium of degree of oxidation zerois obtained.

(D) 3.79 g. of the complex-forming polymer prepared as described inparagraph (A) are stirred, at about 20 C., with 100 cm? of an aqueoussolution of chloroplatinic acid, H PtCl containing 1.2 milligram atomsof platinum per litre. After 12 hours stirring 0.04 milligram atom ofplatinum per litre remains in solution.

(B) 1.09 g. of the complex-forming polymer prepared as described inparagraph (A) are stirred, at about 20 C., with 50 cm. of water in which100 micromols of cupric nitrate and 5 millimols of nitric acid have beendis solved. After 12 hours stirring, 1.8 micromols of cupric salt remainin solution and the pH is 1.0.

(F) 0.965 g. of the complex-forming polymer prepared as described inparagraph (A) is stirred, at about 20 C., with 50 cm. of water in which100 micromols of cupric nitrate and 50 millimols of sodium nitrate havebeen dissolved. After 12 hours stiirring, 1.15 micromols of cupric saltand the amount of sodium salt initially employed remain in solution.

(G) 1.109 g. of the complex-forming polymer prepared as described inparagraph (A) are stirred, at about 20 C., with 50 cm. of water in which100 micromols of terric nitrate have been dissolved. After 12 hoursstirring, 0.65 micromol of ferric salt remains in solution.

EXAMPLE 11 4 g. of 4,4'-dimethyl-2,2'-dipyridyl and 12 g. ofterephthaldehyde are introduced, under an inert atmosphere, into a 250cm. flask equipped with a reflux condenser. The mixture is heated to 150C. for hours and washed with 400 cm. of boiling ethanol. The residue isrecrystallized from 100 cm. of N-methylpyrrolidone-Z and then driedunder 200 mm. of mercury pressure at 50 C.

4.5 g. of 4,4-bis(p-formylstyryl)-2,Z-dipyridyl of formula:

are obtained.

We claim: 1. A complex-forming polymer consisting essentially of repeatunits of the formula:

rated, linear or branched radical or a said radical carrying hydroxyl or0x0 substituents, not more than 2 hydroxyl substituents and not morethan 1 0x0 substituent being present per repeat unit, or a said radicalin which one or more pairs of carbon atoms. of such radical areconnected by alkano or alkeno bridges, said radical containing a totalof less than 12 carbon atoms; and R represents a phenylene radical. 2.The complex-forming polymer of claim 1, consisting essentially of repeatunits of formula:

3. A process for the preparation of polymers defined in claim 1 whichcomprises subjecting to polycondensation with reactive comonomer offormula:

in which R is as defined in claim 1, a dinitrogenous monomer having itsstructural skeleton identical to the skeleton of the compound of theformula:

in which L, a and a are as defined in claim 1.

References Cited UNITED STATES PATENTS 2,739,948 3/1956 DAlelio 2602.13,553,180 1/1971 Cleary 260-8072 LESTER L. LEE, Primary Examiner US. Cl.X.R.

260-62, 63 R, W, 77.5 AQ, 78 R, 88 PA, 88.3 R, 93.5 R, 283 R, 294.8 G,295 R, 296 D

